Various hydraulic retractable and extensible wheel suspension systems have been provided for vehicles wherein the vehicle may be hydraulically raised to a transporting position or lowered to a ground level position to facilitate loading or unloading the vehicle. While these systems have been satisfactory for their intended purpose, they have been characterized as being complex, having many moving parts and requiring the design and construction of an axle and wheel suspension for use on the particular vehicle.
After considerable research and experimentation, the hydraulic retractable and extensible wheel suspension of the present invention has been devised for use on trailers, particularly concession trailers manufactured for food service, wherein a standard off-the-shelf axle assembly is pivotally connected to the trailer frame at a point offset from the wheel spindle and axle, whereby the floor of the trailer can be brought extremely close to the ground. A hydraulic cylinder is operatively connected to the axle assembly for pivoting the axle assembly about the offset pivot point, to thereby raise and lower the trailer.